Digital SLR Astrophotography

This tutorial covers the methods I use for astrophotography with my Canon XSi digital SLR and Celestron CGEM. It is similar to the tutorial I wrote in December of 2007 for digital SLR astrophotography with my Canon 300D. With the exception of the Orion ED80 refractor, I am using all new equipment. I am also using different software for processing the RAW images into a detailed composite photo. Note that there are different ways of going about astrophotograpy with a digital SLR. In fact, there are probably better ways. This tutorial depicts the methods I used for capturing the example images below. I hope you find my new tutorial useful and please feel free to ask questions or add comments in the “Leave a Reply” section at the end of the tutorial.

Example Images

The images below are provided as an example of what can be achieved with an equipment setup similar to mine and the methods provided in this DSLR astrophotography tutorial.   

Astrophotography Equipment

Digital SLR Astrophotography Equipment
My Digital SLR Astrophotography Equipment

Here is an overview of the equipment I use for DSLR astrophotography. My setup is not considered a high-end system by any means, but nice results can be obtained. First, the telescope is a Celestron CGEM Mount with the Orion ED80 Telescope as the imaging scope. Piggybacked to the ED80 is the Orion Awesome Autoguider Package. Included in this system is the ShortTube 80mm refractor and StarShoot Autoguiding camera. I endorse this autoguider in various articles on my website because it is a complete, low-cost system that gets the job done. Autoguiding has made a big difference in the quality of my images since I wrote the DSLR astrophotography tutorial in 2007. And finally, I use the Canon XSi (450D) as my imaging camera.An important note here is that my ED80 refractor and Canon XSi DSLR are a good match optically. That is, the pixel size of the DSLR sensor matches the resolution of the telescope. This is explained further in my article- DSLR Astrophotography Calculator.

Also worth mentioning, I use an extension cable for my NexStar hand controller since the original cable was too short. The extension cable add-on gives me an extra seven feet of cord length so I can move freely around the telescope. Extension cables for the NexStar hand controller are available here on AstroPhotography Tonight.

Here are the links to my equipment reviews here on Astrophotography Tonight: Orion Starshoot Autoguider ReviewCelestron CGEM Review Part 1Celestron CGEM Review Part 2, Celestron CGEM Review Part 3, Celestron CGEM Review Part 4, CGEM Astrophotography- The Next Phase, NexRemote Telescope Control for CGEM

Telescope Setup

Before attaching the DSLR, I perform a decent polar alignment and 2-star alignment for the CGEM’s goto functionality. For polar alignment, I normally use the drift alignment technique as described in my CGEM Drift Alignment Procedure. Alternatively, the CGEM mount has a polar alignment routine called “All-Star” that works pretty well for fast polar alignment. The main point is that a good polar alignment is important for long exposure astrophotography. This is true even with autoguiding since you will need to keep the object still in the field of view while setting up the autoguider.

Goto functionality is not necessary, but I have found it to be VERY helpful for getting the object into the digital SLR field of view without the finderscope. The CGEM’s goto capability is very accurate in my experience. Plus, when it’s time to move on to another object, it’s a snap!

Attaching the Digital SLR to the Telescope

Once the telescope alignments are complete, I then slew to the target that I want to image. At this point, the telescope reticule eyepiece is still inserted from the alignment process. If the object is bright enough, I will center the object in the field of view if necessary. Otherwise, I do this later with short exposures and hand controller adjustments. More on this in a bit. Once the telescope is pointed at the target, it is time to remove the eyepiece and insert the camera.

Connecting the digital SLR to the telescope requires a T-ring and T-adapter as shown below. The following steps show how to attach the DSLR to the telescope.

T-Ring and T-Adapter for Digital SLR Astrophotography

Step 1: T-adapter and T-ring are separate components. Note that the T-ring must be specific to the type of digital SLR used.

Step 2: The T-adapter and T-ring are threaded. The two components are combined.

Step 3: Attach to digital SLR. The T-adapter/T-ring assembly inserts into the DSLR just like the camera lenses do.

Step 4: Attach digital SLR to telescope. The DSLR with T-adapter/T-ring assembly is inserted into the telescope eyepiece holder directly (i.e., no eyepieces, Barlows, etc are used). This is considered “prime focus” astrophotography. The telescope optical tube serves as the camera lens.

Important tips: tighten the telescope thumbscrew to the T-adapter securely. Also, be sure to attach some type of DSLR strap to the telescope in case the camera falls.

Digital SLR Computer Connection

One thing really nice about my Canon XSi is that I do not need a special shutter control cable like I did with the Canon Digital Rebel (300D). The XSi uses a standard USB cable that works in conjunction with the EOS Utility that came with the camera. I actually have a remote connection to the XSi and telescope using buried Cat. 5e cable that runs in Schedule 40 conduit from my telescope to control room in my garage.  On both ends I use simple USB to Ethernet adapters. If there is enough interest, I can document this remote setup. Just leave a comment in the “Leave a Reply” section at the end of the tutorial. Not to worry, my tutorial works the same if you are using a laptop at the telescope. My remote setup is nothing more than extensions of the USB cables. Most of my work is done indoors where it is comfortable!

At this point, the telescope is pointed at the object that I want to image and the DSLR is inserted in the telescope. With the USB cable already connected to the computer and XSi running on AC power (with optional adapter), I turn on the camera.  The camera mode dial should be set to manual as shown below:

Mode Dial Set to Manual for DSLR Astrophotography

If everything is connected correctly, an autoplay pop-up will appear on the computer screen:

DSLR Connection- Auto Play

Just cancel this pop-up by clicking the red “X” in the upper right corner. Open the EOS Utility that came with the DSLR.

EOS Utility Instructions

1. Upon launching the EOS Utility, the camera control screen will open as shown below. Click on “Camera settings/Remote shooting”.

EOS Utility for Digital SLR Astrophotography

2. This will bring up the main interface for remote operation of the XSi. Note that it is already set to manual from the mode dial setting earlier. In order to take long exposures, the DSLR must be set to “bulb”. In the screenshot below, it is already set to bulb. By default, it may be on another exposure setting. To change to bulb, simply hover your curser over the icon (where bulb is shown in the screenshot) and right-click (or double-click). Now click on the left double-arrow button and it will go to the bulb setting. Now just move the cursor away.

EOS Utility Settings for DSLR Astrophotography

Do the same for the other settings in this area. The screenshot above depicts the settings I used last time I imaged.

Shooting mode: bulb

White balance: daylight (popular setting)

ISO speed: 1600 (this varies depending on the object)

Metering mode: evaluative metering (which was default)

Image recording quality: RAW (maximum data)

Image save location: computer (images automatically upload to computer after each exposure is complete)

DSLR Test Shot

At this point, it is time for a test shot to see how well centered the object is and how much focusing is required. To take a a shot, press the shutter button at the top right hand corner of the EOS Utility interface.

DSLR Shutter Button
Click the Shutter Button to Start the Exposure

For bright objects, I only take about a 1 minute exposure but perhaps 2 minutes or more for faint objects.  The shot duration will be displayed in the window to the left of the shutter button. Be sure to click the shutter button again once the desired amount of time has elapsed. This will stop the exposure and the image will automatically transfer to your computer and will display in the quick preview window.

Object Centering

If the object is not in the center of the field of view, I simply make fine adjustments with the telescope hand controller. First, I turn the slew rate down to about five and press one of the directional buttons on the hand controller for about 3 seconds. Then I take another test shot to see how the object moved in the field of view in comparison to the initial test shot. I make note on paper of the movement that the directional button caused. This process is repeated a few times with other directional buttons and documenting the effect. Once I know what direction the object moves for all of the directional buttons, I can center the target nicely in the field of view. This process actually goes fairly quickly and is much easier than trying to center the object through the camera viewfinder! Here is and example of the notes I took during a recent astrophotography session:

Directional Button on Hand Controller Direction that the Object Moves
Left Up and Right
Right Down and Left
Up Right and Down
Down Left and Up

Telescope Focusing

After the object is centered, I will start the focusing process. Note that many times I will actually focus while I’m centering the object since it minimizes the number of trips to the telescope (remember I’m imaging remotely). For focusing, I use the popular Bahtinov focusing mask. This thing makes focusing very simple and quick! The mask just lays over the end of the telescope tube. Then I take trial shots with the digital SLR and adjust focus until the diffraction spike pattern is symmetrical. The video below demonstrates this process on a SCT rather than the ED80 that I use. It is the same process though. Note that many times I further fine-tune the focus after my autoguider is going (discussed in the next section). This makes for a cleaner image for determining the symmetry of the diffraction spikes. Make sure that you remove the Bahtinov mask when the focusing process is complete!


Autoguider Setup

After the initial focusing is complete, it’s time to fire up the autoguider. I am using the low-cost Orion Awesome Autoguider Package. The Orion system is composed of the following items:

  • Orion ShortTube 80 refractor telescope
  • StarShoot AutoGuider
  • 1.25″ Extension tube (for camera focus)
  • Guide scope rings
  • Guide scope ring mounting bar
  • 10′ USB cable
  • 6′ autoguide interface cable

The autoguider is piggyback mounted to the top of my ED80 imaging tube with adapters from ADM Accessories. Note that the Orion Autoguider is “ST-4” compatible so it works with most equatorial mounts with an autoguide port.

The connection of the Starshoot autoguide camera is very simple. There are two cables- an autoguide interface cable and a USB cable. The autoguide interface cable plugs into the back of the autoguiding camera and plugs into the autoguide port of the telescope mount. The USB cable connects to the back of the camera and into USB port of the computer.

Starshoot Autoguider Connection

The Orion autoguider runs off of the software program PHD Guiding which was developed by Stark Labs(as a freeware program) to be a simple way to guide your telescope. Once the autoguider is plugged in, I launch the PHD Guiding program on my computer and begin the setup. Here is my review of the Orion Autoguiding System. Note that toward the end of the review I have provided a quick start procedure with corresponding video. This is the basic procedure for setting up the autoguider and locking on to a star. Once I am guiding, I normally do another fine tuning of the focus with the Bahtinov mask still in place. When I have achieved perfect focus (at least as good as possible), the mask is removed and it is time for collecting some frames!

Collecting Light Frames

The EOS Utility remains open throughout the process of setting up the autoguider. At this point, I take a decent-length trial exposure of the object. I will use M31 The Andromeda Galaxy as an example for this part of the tutorial. A 5-minute exposure of M31 is a good starting point. Before going too far, I should make mention of file uploading from the DSLR to computer. When each exposure is complete, it automatically uploads the image to a specified directory on your computer. It’s easy to select a directory in the EOS Utility:

  1. Click the “Preferences” button at the bottom left of the utility.
  2. This brings up the Preferences box. Click on the “Destination Folder” tab.
  3. To the right of the Destination Folder field, click the Browse button.
  4. Set up a new folder in the location of your choice and save.

A typical directory structure for me goes like this:

Astrophotography>11-28-10>M31>5min lights ISO1600

So the trial 5-minute exposure would go into this directory. If it looks good, it will become part of my collection of light frames. Assuming that everything looks good with the trial photo, it’s time to setup the interval timer for the first set of light frames. The EOS Utility has a pretty nice automatic shutter control program. To set it up, click on the interval timer button:

Interval Timer for DSLR

This brings up the Timer Shooting Settings box as follows:

DSLR Timer Settings

Delay time: the amount of time (in seconds) before the “first” exposure starts.

Interval timer shooting: the amount of time (in seconds) until the next shot will be taken. This provides time for the previous image to upload to your computer. This time has to be longer than the exposure time.

Shots (minimum 2): the total number of exposures to be taken.

Exposure time: the total length of time for the shutter to be open taking the image.

Once the Start button is clicked, the DSLR automatically starts the shutter control routine based on the timer shooting settings. This is a nice time to take a break and go get coffee!

It is normal in my experience for the RAW images to be washed-out and have a reddish-cast to them (probably from light pollution). This is especially true with long exposure times. Here is a single 10-minute frame of M31 taken at ISO 1600. It’s no problem though, the reddish-cast will be eliminated through the stacking process!

Digital SLR Single Exposure

Various exposure lengths ISO speeds are used in DSLR astrophotography. My image of M31 at the beginning of this tutorial was taken over the course of several nights. I collected data at various exposure times and ISO settings. Here are the settings I used for the composite photo (all taken at ISO 1600):

  • 30 frames at 5 minutes each
  • 3 frames at 10 minutes each
  • 4 frames at 7 minutes each

Important tips: make sure you have achieved the best focus possible. Take lots of light frames! The more frames that you stack, the better the signal-to-noise ratio (more signal, less noise).

Collecting Dark Frames

The purpose of taking dark frames is to subtract them from the light frames later in the process. This helps to eliminate thermal noise in the image caused by the build-up of heat on the imaging chip. Dark frames are taken with the same exposure time and ISO settings. The process is simple:

  1. Cover the end of the imaging telescope with the dust cap. Note that it must be a tight fit so no light will reach the telescope optics. The DSLR must take exposures of total darkness.
  2. Follow the same procedure for collecting light frames above. I always create a dark frames directory for the exposures to upload to. Here is an example: Astrophotography>11-28-10>M31>5min darks ISO1600.

My preference on dark frames is to take a set after each set of light frames for each ISO/exposure time setting. I don’t always take as many dark frames as I do light frames though. So the imaging session for my M31 example above looks like this (in order of operation):

  1. 30 light frames at 5 minutes each at ISO 1600
  2. 5 dark frames at 5 minutes each at ISO 1600
  3. 3 light frames at 10 minutes each at ISO 1600
  4. 3 dark frames at 10 minutes each at ISO 1600
  5. 4 light frames at 7 minutes each at ISO 1600
  6. 4 dark frames at 7 minutes each at ISO 1600

After collecting all the light frames and dark frames, it’s time to start the processing phase.

Processing in DeepSkyStacker

DeepSkyStacker is a popular freeware program that allows you to register and stack all of  your frames including lights and darks. DeepSkyStacker can be downloaded here.

For my astro-photos that this tutorial is based on, I only used DeepSkyStacker at it’s most basic level. Thus, I loaded the light frames and dark frames then processed them with default settings. Here is the basic procedure:

    1. Launch the DeepSkyStacker program.
    2. In the upper left menu (under Registering and Stacking), click on “Open picture files…”. Now select your first set of light frames. To select multiple files, just hold the shift key down and click on the first file in the set and then click on the last file in the set. This will select the entire set of files. Click the Open button when all files are selected. Repeat this step for other sets of light frames (i.e., if you had other sets with different settings in other folders). Be sure that only good quality light frames are loaded. It’s a good idea to review all the images prior to this step to eliminate any that are of poor quality.
    3. Click on “Dark files…” in the same section. Repeat the step above but select the dark frames that were captured. Include all dark frames for each set of light frames.
    4. Across the bottom of the DeepSkyStacker screen will be a list of all frames that were loaded. Here you will see the details for each frame that is loaded. Note that the column of boxes on the left side of the list are not checked. Just go back to the menu on the left side of the screen and click “Check all”. This will automatically check every box in the list for processing.
    5. Once all of the frames are selected, click “Register checked pictures…”. The Register Settings box will pop up:

DeepSkyStacker Settings

I just leave the default settings as shown above and click the OK button.

    1. Now the Stacking Steps box appears. Again, I leave everything default and click the OK button.

DeepSkyStacker Settings

  1. Now DeepSkyStacker begins the automatic processing phase. This part can take several minutes depending  on how many frames are involved. Basically, the program creates a master dark frame, does registration, subtracts the master dark frame, computes offsets, and stacks the frames together for a final composite image.
  2. Click “Save As” and save as a 16-bit TIFF image.

Here is the DeepSkyStacker output (cropped and resized). There is still much work to be done, but the composite image from DeepSkyStacker is loaded with information that will be drawn out in the next steps.

Deepskystacker Output- DSLR Astrophotography

ImagesPlus Digital Development

This next step is performed in the program ImagesPlus. In the past, I used ImagesPlus for DSLR control and image set processing. However, with the new Canon XSi, I use the EOS Utility for camera control and DeepSkyStacker from most of the image set processing (as discussed above). However, I still like the Digital Development tool in ImagesPlus for enhancing the composite photo. I hope to eventually provide an alternate method in PhotoShop in case you do not have ImagesPlus.

  1. Launch the ImagesPlus program.
  2. Open the image file that was saved in DeepSkyStacker. Go to the Color menu, Brightness Levels and Curves, and select Digital Development. Reference screenshot below.
    Enable Sliders.
  3. Pull the Break-Point slider to the left until the desired amount of detail obtained.
  4. Bump the Backgd Wt. slider slightly to the right to darken the background a bit.
  5. Click the Done button when finished.
  6. Save the file as either a 16-bit Uncompressed TIFF for further processing in PhotoShop (next section).

Here is the ImagesPlus output. As you can see, the Digital Development tool really brought the image to life! Now just a few tweaks are needed in Photoshop.

ImagesPlus Output- DSLR Astrophotography

Further Processing- Adobe Photoshop

I won’t spend too much time on this part. Basically, the following tools in Adobe Photoshop are used to clean up the photo for the final version:

  • Crop (to center image)
  • Rotate canvas (for proper orientation)
  • Levels (tonal range and color balance)
  • Unsharp Mask (sharpens image but introduces noise!)
  • Color Balance
  • Hue & Saturation

Photoshop Astrophotography Instructional DVD

Learn to work with the basic Photoshop tools such as menus, layers, masks, and keyboard shortcuts. Making Every Pixel Count will help you learn your way around Photoshop.

Learn higher level concepts and procedures for processing astro-images such as LRGB production, high-pass filters, star replacements and substitutions, sky and star adjustments, noise reduction, star repair, and much, much more! Adam’s Block’s Making Every Pixel Count DVD contains 25 sections of on-screen training adding up to 9 1/2 hours of instruction!

Available here on AstroPhotography Tonight!

Final Image!

DSLR Astrophotography- Final M31 Image

Tips & Tricks

  • Balance the optical tube in the area of the sky that you will be imaging in. Make sure it is loaded with all the equipment you will be imaging with. The main purpose for this is so the gear mesh or backlash is minimized so that the telescope doesn’t have to take up slop and the autoguider has to take longer to track on the star due to this slop. It helps minimize strain on the gears and motor so that the telescope can track smoothly.
  • After focusing the DSLR for the first time, use a fine permanent marker and draw a short line on the telescope draw tube where it enters the telescope. This will make it much easier the next time to get the focus close for the DSLR.
  • It may be helpful to focus on a bright star before slewing the telescope to the target object. The diffraction spikes (from the Bahtinov focusing mask) may be clearer and more distinct with a bright star making it easier to determine thier symmetry.

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  1. AstroPhotography Tonight

    Please feel free to add comments or ask questions here regarding my article: “Digital SLR Astrophotography”.

    Ray Shore

    1. Jeff McClure

      Ray, I have a 60Da (new) and last week got a knock-out image of the Great Orion Nebula using five ten-minute exposures at ISO 6400 through my Skywatcher 120ED. The only thing I changed from last week was to remove the 0.85x reducer/flattener. Last night i shot three 20 minute exposures of the Horsehead Nebula and wound up with a very dark image with only hints of the nebula. I can get a vague image by stretching the heck out of the results, but with the resultant extremely grainy appearance that comes with that.

      I really don’t think that the Horsehead is that much dimmer than the fringes of Orion, which came through beautifully last week. Both nights were clear and nearly cloudless and cold. Location was the same. HELP!

      1. AstroPhotography Tonight

        Hi Jeff, one thing might try is to add more light frames so you can stretch it more before the noise becomes a problem. See my article regarding my last image of the Horsehead Nebula : My exposures were :
        5 x 10min at ISO1600, 10 x 5min at ISO800, and 5 x 8min lights at ISO800. I collected these over 2 nights. I hope this helps! Ray Shore

    2. Ray great article! Would you provide more details on the usb-Ethernet link, please? Thank you.

      1. AstroPhotography Tonight

        Sorry I didn’t get back to you on this yet. I use USB over Cat5e extenders like these shown here. Basically, I ran Cat5e cable underground and terminated each end on Cat5e jacks like these. The jacks were inserted into Keystone style surface housings like this. I just plugged one of the USB over Cat5e extenders into my computer’s USB port and connected an ethernet cable into the other end and into the Cat. 5e jack. The other end at the telescope plugs into the Cat. 5e jack and then provides a USB port for the telescope equipment. I need to put together a diagram to help demonstrate. Please let me know if you have any questions. Thanks, Ray Shore

        1. I see, Thanks for the information. Am I correct in the following sequencing?
          Device -> USB to Cat5 extender -> Cat 5 jack-> Ethernet cable underground/behind walls ->Cat5 Jack->USB- Ca5 extender – Computer.

          1. AstroPhotography Tonight

            Lathif, that looks correct. One note, I ran the cat 5e cable underground in schedule 40 conduit. Ray Shore

    3. Very simple and concise description of the steps required to do Astrophotography with a DSLR. Great help for beginners. It would be agreat addition to have a step by step processing flow for adding additional detail in Photoshop and with the same degree of detail. Nice job.

    4. Henri-Julien Chartrand

      Dear Ray,
      Finally, a clear step by step article for a newbie like me. I just receive a new Canon Rebel T3i camera and I will now be able to better plan trial sessions thanks to you.
      Respectfully, HJ Chartrand P.S. If you have any updates, post them up.

    5. Hi Ray, I’m new to astrophotography, and I have a canon eos T3 with a celestron power seeker. I have the proper attachments for the camera, and the scope, and I’ve tried various settings on the camera to get the right exposure for stacking using deepskytracker, the only thing i don’t have is a auto guide for the scope, ( kinda lacking in budget) so I tried using multiple shorter exposure time shot to create my white frames, while positioning the telescope after each shot.
      What can I do to try and get some better shots before I have the finances to pay for a more high end setup?

      1. AstroPhotography Tonight

        Hi Jeremy,
        What optical tube do you have? Also, how long were the exposures you took?


        1. I’m using a reflector tube,
          I tried various exposure times , from 5 seconds to 10 seconds shots to 30 second shots, Since I don’t have a drifter mount, I can’t do very long exposure since they turn to nothing but a blur. Also I’ve tried looking for a Photoshop compatible ArcSinh plugin, but none seems to work with photoshop CS4. so I have no idea how to do the stretching.

  2. Great tutorial Ray! I am in the process of getting my equipment together to start imaging. I am going to have a setup very similar to yours. The only difference is the mount, I think I’m going with the Orion Sirius EQ-G. I really appreciate all of your hard work you have put into this website!

    1. AstroPhotography Tonight

      Thanks for the nice comments Trevor! I think the Orion Sirius EQ-G would be a good choice. That mount and the Atlas are very popular for astrophotography. What DSLR will you be using?

      Best of luck with your imaging!

      Ray Shore

  3. Hi Ray,
    another great tutorial you did here! Also pleased to inform you that I have ordered my own CGEM mount today. So when it arrives I can put many of your tutorials into practise 🙂

    Please, keep up the good work!


    1. AstroPhotography Tonight

      Hi Robert!

      Thank you for the nice feedback! It is great to hear that you have ordered a CGEM. You will love it! So what optical tube did you get with it? Hope to see some of your work!

      Ray Shore

  4. Hi Ray, I got a 10″ photo Newton with it. I will use off axis guiding, together with a Lodestar autoguider to shoot images. I hope to show you something soon (for one thing, I need clear skies for that, which have become very rare lately) 😉


  5. Ray–

    I learned a lot from your first tutorial. The second taught me more. Thank you for both productions.

    I use ImagesPlus for both camera control and processing. I don’t have PS. (I’m a’gonna get it!) I use Nikon NX2 in lieu of PS. (It won’t do layer masking. :()

    I have the SSAG package on top of an AT8IN with a Nikon D700. Mike Unsold is going to drop Nikon from the camera control package. So a change is somewhere in my future. I am contemplating CCD.

    I use an Orion Atlas EQ-G, which I think is similar or identical to your CGEM, without that fantastic “All Star.”

    Your ED80 shots are very impressive! I bet that refractor is a lot easier to use than any kind of reflector. Plus, it places very little load on your CGEM.

    (Almost) OT: What software do you use for your web site? Do you know what kind of software “most” use for their web sites? Mine is all early 1990s vintage hard-coded HTML. I sure would like something easier with more flexibility.

    ps daltonstargazer told me you and I live within a dozen miles, or so, of each other.

    1. AstroPhotography Tonight

      Hi Bill,

      Thanks for the feedback on my tutorials. It’s always nice to hear that they are useful! Jeff over at DaltonSkyGazer told me about you awhile back. He said that you are capturing very nice images. I just saw your image gallery on your website and I agree with Jeff…very nice work! I have been interested in the 8” Astro-Tech AT8IN optical tube since it will have much more light gathering ability than my ED80. Very nice to see your results! Maybe I will try it someday. I am pretty happy with the ED80…it has been a nice scope for astrophotography. Sounds like you are located fairly close to me. I am in Paola, Kansas which isn’t too far south of Kansas City.
      I use the open source program WordPress for this website. It’s a really nice program especially if you want a blog type of website. Another nice open source program that I’ve used for other websites is Joomla. My older astrophotography website: is built on a program called Namo. It’s just a simple web page software program that I bought at the store.

      Keep in touch!
      Ray Shore

    2. bill, i’m getting a at6rc. did you need an extension tube to set up your d700 on the at8rc?

  6. Nice job, Ray!! Finally took my time to really absorb your wonderful tutorial and learned some very useful new tricks! For example, Images Plus is a software I have never used – I always went straight from Deep Sky Stacker to Photoshop. I am very curious to try it out.

    Thanks much!


    1. AstroPhotography Tonight

      Hi Martin,

      I used to use ImagesPlus for the shutter control program and stacking. Now I just use it for that Digital Development tool that works like magic! I’m glad my tutorial helped 🙂

      Clear Skies!

      Ray Shore

  7. Vlassios Marangos

    Hello Ray !
    I am Brazilian, I’m 51 years old, and am researching a lot to get start this wonderful hobby that is the astrophotography. Here in Brazil all the equipment you use are very expensive and just thinking of importing the equipment discourages start this hobby. But I want to congratulate you for your website is very comprehensive and instructive, very good, if i am not wrong, is the best I’ve seen so far. I will use it as a reference and hope that you can help me with doubts that i will have. Canon 5 D Mark ll and 1 D Mark lll, are very expensive …. I’m considering buying the Canon 550 D T2i because is in production today and is one of the cheapest with all necessary resources for astrophotography … relying with your knowledge and experience, you recommend me buy this camera? and advises me to replace the low-pass filter this camera by one astronomical filter ?. Knowing that i can count with your help, thank you in advance, thank you!
    Clear skies!
    ps. I do not know the language very well and I’m using the Google translator to speak with you. I’m sorry if any word is unclear.

    1. AstroPhotography Tonight

      Hello Vlassios

      Thank you for the nice comments about my site. I haven’t used the Canon 550D T2i but I have seen some good reviews about it. One review shows that it has less thermal noise than the Canon 20Da and the Canon 1000D. I’m probably not a good one to recommend removing the IR filter since I’ve never done this. I’m taking some pretty good photos with my Canon XSi without it being modified. I assume that the results would be better for certain objects if the filter was removed. I just don’t have experience with it to make a recommendation! I may try it someday.

  8. Larry Hardman

    Hi Ray, this is one of the best start to finish tutorials I have read so far. The web is a great place for information but it is not usually all pieced together. I have been reading and reading trying to come up to speed on what to buy for hardware, software and books on the subject so I can make the best cost effective decision. I was going to get a Nikon but then saw that the majority of people are using Canon and there seems to be more software support for it. I just used my Delta Skymiles to order a free Canon Rebel T2i which will save me a boat load of money. I will look again at the CGEM mount and compare it to the Orion Sirius. I was also going to get the Orion 80ED and the Orion auto guide package. A couple of questions. Why are you not using the Orion reducer/corrector between the T-ring and focuser? I am assuming you have the mount tracking turned on and are using the auto guider to make minor adjustment? I have read about the modified Canon cameras and the Hutech and Astronomik filters you can attach to the camera for filtering. I am confused if you can also put some of these broadband or light pollution filters in line in the t-ring to focuser connection. If so would this not be the cheapest and easiest way of using filters with a DSLR? Lastly when I see what equipment and software people are using I see so many software/hardware/freeware solutions people are using. Maybe this is because there were no intergraded solutions when they first started out with AP or they are trying to save money using some freeware. I am surprised there are not more in depth reviews and write ups of the functionality and workflow of the complete Image Plus package. If you are building a new system this seems to be the way to go but this is where I cannot find enough information. Thanks for sharing, Larry

    1. AstroPhotography Tonight

      Hi Larry, thanks for the nice feedback about my tutorial. Nice that you are getting the T2i with your Skymiles! It should be a capable camera for astrophotography. I think for the money, the CGEM and the Orion Sirius (or Atlas) would be a good choice. I went back and forth between the CGEM and the Atlas but finally settled on CGEM. I’ve been looking at the Orion reducer/corrector. It actually puts the arc seconds/pixel closer to the sweet spot of 2.0. Correct on the autoguider. I do a close polar alignment then use the autoguider to keep the tracking right on. Very good question on using the broadband and light pollution filters in line when using the Orion reducer/corrector. The filters screw into the t-adapter but only the t-ring is used with the reducer/corrector. Will have to investigate further to see if we can also use the filters. Very good question! My tutorials offer some information on using ImagesPlus but I haven’t actually written a review on it. I’m not using ImagesPlus as much as I used to. Now I use DeepSkyStacker for stacking the images and the Digital Development tool in ImagesPlus to enhance the stacked photo. Here is my latest tutorial that explains the process: Thanks again for your feedback and I wish you the best with astrophotography! P.S. let us know if you figure out the reducer/corrector and filter thing! Ray Shore

  9. Larry Hardman

    Hi Ray, great idea on the USB Cat4 extender. I bought one for a test using the EOS utility and it turned out to be only USB 1.0 compliatnt and took about 25 secs to download an image. What model/brand are you using? Seems you could place a USB hub at the telescope end and control the camera and autoguider with just one extender. I saw where another person with 80ED was using an extender/flattener from Williams Optics which allows filters at the nose end. It also allows you to easily rotate the camera to orient your subject. It is pricey but here is the link. Seems you can save $60-70 by buying imageplus without the camera control and use the EOS uitlity to control the camera. Thanks, Larry

    1. AstroPhotography Tonight

      Larry, I am using the Cables Unlimited USB-1370: It doesn’t give me USB 2.0 speeds but seems to be working ok anyway. I’m downloading the RAW’s directly to my computer in under 10 seconds. 25 seconds would be a long time! I have heard of people using a USB hub at the telscope end so I’m sure it works. Another way that seems to be popular is to set the laptop at the observatory and run your programs on it such as the EOS Utility and autoguider software then take control of the laptop from a computer inside the house. You can either take control wirelessly or use a powerline adapter which sends the ethernet signal across the AC line. Thanks for sharing the link for the Williams Optics reducer. I will check it out. Yes, you should be able to buy just the ImagesPlus processing program without the camera control program. The EOS Utility works pretty nicely. Thanks, Ray Shore

  10. Ted Gardner

    Hello again Ray. I keep coming back to your site for the tutorials as I find them a very, very valuable! I’m starting into astrophotography using the XSi camera as well with the remote control with my laptop. Since Spring is starting here in Georgetown, Ontario, I came back to your description of your remote setup with the telescope and XSi with Cat 5e cable. I hope there has been enough interest that you are considering documenting this setup.

    In any event, your pictures are amazing, especially those using Images Plus Digital Development. They come alive!

    Also, would you be interested in putting on a seminar for your topics on your website? I think you might have enough interest from other amateur astronomers. If you ever do, please let me know.

    Best Regards,

    1. AstroPhotography Tonight

      Hello Ted. I’m glad to hear that my tutorials are useful! I’ve got plans to write more but haven’t had a chance. The next one will be about my most recent photo of the horsehead nebula: I finally got an image of this difficult object that I’m pretty pleased with. I still plan to do an article on my remote setup too. Sorry I haven’t posted one yet.
      Sure, I might do a seminar someday for some of my topics. That would be fun! Thanks for all the nice comments!
      Best Regards,

  11. Ray,

    Would you mind itemizing exactly which ADM adapters and rings were required to mount the scopes on the CGEM in your setup?


    1. AstroPhotography Tonight

      Hi Rob, here you go:

      Bottom dovetail for ED80: DMM7 fits in the CGEM’s saddle plate. Here is the link for the DMM7:

      On top of the DMM7 is the dovetail ring & adapter set. I bought these a
      long time ago (for my LX200 dovetail plate) so I’m not sure which ones
      they are on ADM’s website. The rings are the clamshell type which I
      don’t see on their site anymore.

      The ED80 sits inside these rings. On top of the rings are the Vixen
      Dovetail Plate Adapters shown here: I bought 2 of
      them…one for each ring. The dovetail bar that comes with the Orion
      Awesome Autoguider fits in these adapters.

      You might contact ADM to on the components that I’m not sure about. I worked
      with Anthony Davoli on my setup ( I told him
      that I wanted to mount my ED80 directly to the CGEM saddle plate then
      mount the Orion Autoguider to the top and he pointed me to the right
      adapters. I hope this helps! Thanks, Ray Shore

  12. Fantastic write-up Ray! I too am just getting started. I decided to spend the bulk of my tax refund on Astro-imaging equipment. I have a CGEM with an Orion autoguider package on the way. I also have a XSi being modified by Gary Honis.
    I plan on using my Canon 200mm F1.8 lens quite a bit, and may try the Astro-Tech 10″ F/4 Newt if it isn’t to heavy for the autoguider/CGEM to handle. Barring that, I have the Astro-Tech 6″ RC on the way (eventually). All my life I’ve loved astronomy, photography and computers, and I believe this is a great way to combine my loves. Is it OK to keep in touch if I need some pointers? 🙂

    1. AstroPhotography Tonight

      Scott- you are going to have an awesome setup! I know what the CGEM, Orion autoguider, and XSi is capable of especially after my last imaging session of the Horsehead and Flame Nebula: Sure, feel free to contact me any time for pointers: I can’t wait to hear how your new setup works out for you! I wish you the best with astrophotography. Thanks, Ray Shore

  13. Hi Ray,

    Thanks for the help over email that I got yesterday. I later found this updated article which is also interesting (a wealth of information on your site!).

    Question: CGEM mount is pretty expensive relative to the price of your Scope. Any particular reason you went for this solution?

    Lastly, compared to the price of the mount etc, have you given serious thought to removing the ir filter and possibly cooling the camera? If not, what’s the reason?


    1. AstroPhotography Tonight

      Hi Tom,
      It is my pleasure to help! I bought the CGEM because it appeared to be an suitable German Equatorial Mount for astrophotography and meet my future needs. It is best to have a solid beefy mount that can handle a variety of equipment. I may decide to go with a larger optical tube and CCD camera someday so the CGEM should allow for the heavier load. And it makes for a super stable platform for the small ED80!

      I have thought about removing the IR filter. But I wanted to be able to use the camera for normal daytime stuff so I didn’t want to modify it. I may do the filter removal anyway someday. I haven’t really thought about cooling it. I hope this helps!

      Ray Shore

  14. Dear Ray, excellent tutorial ! I´m a brazilian amateur astro-addicted and up to now I was trying to improve my results in planetary images, but now I will go towards DSOs pictures and I know that this quite an even more demanding target.
    I recently bought a Canon T3i and would like to know your opinion about it. My scope is a 254mm newtonian (with GoTo) and I´ll appreciate your recommendations/hints regarding how to begin with DSOs photographs with some reasonable results.
    Thanks a lot and congratulations for your awesome tutorial, very helpful indeed !

  15. Awesome tut, Ray – very informative for those us in the process of seeing what AP is all about.

    At some point I’d like to go with a very similar setup, but I probably won’t go with an OTA larger than the 80ed (I’ll probably get a big dob for actually viewing) Would a CG5 handle an 80ed + autoguider or would I be frustrated?

    Thanks again.

    1. AstroPhotography Tonight

      Hi John,

      I started out with a CG5 for astrophotography. I mostly imaged the planets with it so not a lot of experience with deep space objects and long exposures. I think it would work with the 80ed but it’s not going to be as stable or track as well as some mounts that sell for a bit more like the Orion Atlas EQ-G or CGEM. I know some are getting decent results with their CG5 but not sure how much they have to tinker with them to squeeze out maximum performance. In my opinion, it would be worth saving a few more dollars and getting a little better mount. I hope this helps!

      Ray Shore

  16. Hi Ray,

    You mentioned instead of ImagePlus you might have an alternate method of image enhancement in Photoshop, have you got a tutorial for that yet?


  17. Great tutorial Ray. Question for you. At the beginning of the session you mention that you don’t mount your camera/adapters etc until after the alignment procedure. How do you balance the telescope after mounting the camera without losing your alignment?


    1. AstroPhotography Tonight

      Hi Bruce,

      I usually balance the entire system (including the cameras) before doing the alignment procedure. I’m not sure if this is the best way but I wanted to make sure that everything was balanced during imaging.

      Ray Shore

  18. Ahhh…THAT makes sense. You just do the alignment slightly out of balance then put your camera gear on and you’re back in balance.

    I’m getting ready to attempt my first imaging session so these details are GREAT to know.

    Thanks again for taking the time to put these tutorials and reviews together. They are very much appreciated.


  19. Andrew campbell

    Wow. What a fantastic tutorial. The best I’ve seen yet and believe me I’ve looked at dozens.
    Live the images. I have a similar setup, heq5 mount, autoguider through a short tube 80mm. Zenith star 80mm imaging scope. Canon 30d. I have had some success so far. The only issue I’m having is with deep sky stacker. My single subs have plenty of colour but the final image is very grey and I can’t seem to bring the colour out evenly. Do you have a tutorial somewhere on deep sky stacker? I would love to see your take on it.
    Anyway thanks again for such a fantastic tutorial.

    1. AstroPhotography Tonight

      Hi Andrew,

      Thanks for the great feedback! Unfortunately, I do not have a full tutorial on using DeepSkyStacker. The only instructions are within this tutorial itself showing how to do the basics. I’m not sure what would cause the final image to be grey. I wonder if Digital Development in ImagesPlus would correct this? Although, there should be something within DeepSkyStacker to fix this. I will let you know if I figure anything out.

      Ray Shore

  20. Raul Eduardo Tavarez Ramirez

    This was the greatest and most informational tutorial I have ever read!!!

    I would like to know which are the best imaging products for a Celestron 6SE (I’m interested on deep-sky astrophotography), and if it’s going to be hard to being an astrophotographer for me (I’m 13 years old).

  21. Hi Ray,

    Wonderful write up. I just got my auto guiding kit and your article really cut down the learning curve. My next step is to learn the processing techniques.


    1. AstroPhotography Tonight

      Hi John,

      Great to hear that my article helped! I wish you best of success with imaging!

      Ray Shore

  22. I have both DeepSkyStacker (DDS) and ImagesPlus (IP) for stacking. IP seems to have some difficulty aligning meridian flipped subs. Since you have used both programs, have you found DSS stacked images which are imported to IP for DDP turn out the same as images completely processed by IP? Can the output from DSS, say registered and/or aligned subs, be input to IP?

    By the way, I really enjoy your tutorials. I wish I had found it earlier when I was just starting out. Thanks for you work.

  23. any plans you could e-mail me would be awesome. Thanks for your time, hope to hear from you.

  24. I have just bought a Canon T3 and this tutorial is great a fast short cut to all the information I need to help me with the EOS for the canon imaging capture thanks for the great tutorial


    1. AstroPhotography Tonight

      Jerome – thanks for the feedback. I wish you great success in astrophotography with your Canon! Ray Shore

  25. Richard Chapman

    Hi Ray

    I just wanted to say I have really enjoyed your tutorial, so informative and practical. I am still researching what to buy to get back into Astrophotography after a 25 year gap! Your set up looks great. I don’t think my wife will allow me to have an observatory in the garden or a control room in the garage, but that discussion is a work in progress!

    Best Wishes

  26. This is one awesome site. I just purchased the Cannon 3ti and saw this site. It has already answered several questions that I have had. I have one question, and I apologize as I am a newbie with the Cannon Cameras. Regarding your section of the tutorial using the interval timer. I can’t seem to get mine to come up using the EOS Utility. Is there a setting somewhere on the camera required to enable this?



    1. Hi Gary,
      When you go to the bulb setting in the EOS Utility, is there not even an interval timer icon like in my photo here?


  27. I am a new-bee to Astrophotography. I have a Ioptron ZEQ25GT mount and a Nikon D800 36 megapixel camera (also a Nikon D3s) coupled with either a 70-200mm F/2.8 or a Nikon 200-400mm F/4 lens. I do not know what to expect for my efforts. At this point I do not plan on buying the auto guider scope but if/when I do I will likely get the one you have (Orion Awesome package). I have a lot of reading to do as I do not even know how long an exposure I should take. I have determined the zero position of my mount, nd read up on the correct settings for my camera. I know how to polar align but am not very happy about the polar alignment scope on my moint! When I look into it in my house I see very little – maybe when outside it will be better??? My aim is to start out photographing the Messier objects and start with an easy one – Andromeda. I like the results you have gotten with your Orion ED80 which is 80mm F/7.5. Will my 200 f/2.8 be able to get photos like yours (assuming I have everything set up right and do image stacking etc. Thanks for your time in responding to my comments. Gordon

    1. AstroPhotography Tonight

      Hello Gordon,

      First I have to say, nice choice of mount for astrophotography! I have heard great things about the Ioptron ZEQ25GT. I’ve not used a polar alignment scope but maybe someone else can comment on it. Your 200 f/2.8 should get some nice widefield shots of M31. It will be a wider field than my ED80. Since you will not be using an autoguider, be sure to get the polar alignment as accurate as possible. Fortunately, imaging at f/2.8 is more forgiving when the polar alignment is not perfect and you’re not using an autoguider. Ray Shore

  28. Morris Erickson

    Very nice site. I was introduced to astrophotography by Ray Stinson who was doing classes at Glacier National Park. I just converted a Canon EOS M with a Baader filter (I was a camera repair tech in my past life), and I picked up an iOptron Sky Tracker to get started. Question: The image stacking makes sense to add exposure, but can’t you make multiple duplicates of one image rather than making many separate ones? This would simplify alignment, and an “action” could be set up in Photoshop to process this quickly.

    Many thanks,


  29. @ Morris

    If you stacked a copy of an image you would be using same data each and every time gaining nothing. Each and every light frame is unique in the data that it contains, hence why we stack multiple lightframes. We want to reduce noise, noise in each light frame will vary, by stacking multiple light frames the average noise across all frames reduced and a final clear image is result.

  30. Edgar Ferreira

    Congratulations for this great tutorial webpage.
    It looks by the picture that you use a 1,25 inch T-adapter on the T-ring of the DSLR. Is this better for astrophotography than a 2 inch T-adapter? Im thinking to buy a Vixen ED 80/600 and read something about using a 2 inch T-adapter but it requires also an extension tube? Im confused. Wich do you think is best?


    Edgar Ferreira

    1. AstroPhotography Tonight

      Thanks Edgar! Yes, it is a 1.25 inch t-adapter. I would probably go with a 2 inch T-adapter if that’s the size of your telescope draw tube. I haven’t heard that you need an extension tube though. Ray Shore

  31. Great tutorial. I am just starting in astro photography. I am ok taking light and dark but confused about flats do you take flats and if so how and what benefit do they have.
    Thanks again for any feedback

    1. AstroPhotography Tonight

      Hi Andy, great that you are at least taking darks. To get the most out of astrophotography, it is best to take flats to help remove some of the optical imperfections. However, I can’t really say much about that as I don’t normally take the time for flats :-(.

  32. Hi Ray,

    I’m about to embark on the big astro photography journey,
    I’m setting up a new EQ6 mount, the basic one, and am about to fit the SynScan kit.
    Today I aligned the polar scope to the mount, actually that was today and a fair bit of yesterday, what a bugger of a job till I stepped back and actually thought about what I was trying to achieve. Fitting an ‘O’ ring under the eyepiece helped heaps.
    I’ll be using a Nikon D800 and lens from the Samyang 14mm f2.8 to the Nikon 300mm f4 + T/C’s.
    Ray, I’d like to thank you, firstly for clearing up a lot of grey areas for me, and secondly for your easy to follow step by step tutorial.
    I was very impressed with your results with the Orion ED80 and that, and an auto-guider, are on my wishlist.
    Thank you again for taking the time to help us newbies.



    1. AstroPhotography Tonight

      Hi Kev,

      Thanks for your feedback. Nice to hear that my tutorial was useful! Astrophotography can be a real challenge but rewarding when things go well!

      Best of success on your imaging and keep in touch.

      Ray Shore

  33. Hi Ray, I found your tutorial very informative but on the timer settings you have the interval timer set at 5:15 and the exposure set at 5:00, I have found that I have to set the interval timer to just over twice the exposure time or I get a camera busy signal and it misses the exposure. I use a 40D camera which means I need 4 hours to take 2 hours of images. is this correct or do I have a wrong setting. I am having difficulty finding the second tutorial.

    1. Hi Charles, it seams you have Long exposure noise reduction enabled under Custom function C.FN II, option no. 1. It provides less noise when doing long exposures by doing a second dark exposure, this is why it takes double time before the actual result can be seen. Disable it so you wont lose valuable time. BR

  34. Bob Fitzhenry

    Wow….Thanks so much Ray…..Excellent article for this first time DSLR user. Been looking for a synopsis just like this. Very much appreciated….

  35. John Calvano

    Great primer Ray. Thanks! I’ve been using my grandfather’s C8 (1982’ish) for about 20 years of viewing and started, slowly, getting into imaging a few years back. Everything on Gramp’s scope has been replaced by now, except the actual scope tube itself. Amazed at all the levels of learning ‘required’ to truly enjoy this hobby, and appreciate all the help I can get.
    Your article is a few years old by now, and you may have upgraded by now, but I also wanted to use my scope remotely on cold nights so I use a motorized focuser. Not sure of the name, but will get it if needed, or pretty sure a web search will find one. Mine uses standard earphone-like jacks, so it was a snap to find extension cords to add between the focuser and the handheld.
    Lastly, suspect you probably already know this one too, but I use Carts du Ciel, amazing free-ware night sky mapping software. With enough USB ports, you can point and click, then slew to the object you are interested in, see it in live-view from your camera and track using your Orion tracker. Then with remote focusing, you neve have to leave your chair.
    Thanks again!!

  36. Christopher Edwards


    Where is the video mentioned about focusing with the bahtinov mask please?



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